A37.9
*Notifiable condition
DESCRIPTION
A communicable respiratory infection classically causing a paroxysmal cough followed by an inspiratory whoop (absent in young infants) with associated vomiting. Subconjunctival haemorrhages may be present. The cough can persist for 3 months or longer with the infectious period being between 2 weeks and 3 months. The disease is more severe in young infants where it may present with apnoea rather than inspiratory whoop.
Classic pertussis is uncommon in the vaccine era and most cases present with non-specific respiratory symptoms.
Incubation period: 7–10 days. Range: 6– 21 days.
DIAGNOSIS
- A definitive diagnosis is often not possible and treatment should be initiated in suspected cases prior to microbiological confirmation.
- May have profound leucocytosis, predominantly lymphocytosis, although leucocytosis often absent, particularly in infants.
- PCR on naso-pharyngeal aspirates is the preferred diagnostic modality. Cultures are usually negative, even in confirmed cases. Serology of limited value early in disease.
GENERAL AND SUPPORTIVE MEASURES
- Standard and droplet precautions for 5 days whilst on appropriate antibiotic therapy, for 21 days if not.
- Appropriate respiratory support for apnoea or respiratory distress/failure.
- Encourage oral feeding. If unsuccessful provide nasogastric feeds.
MEDICINE TREATMENT
If hypoxic:
- Oxygen, 1–2 L/minute via nasal prongs.
- Macrolide e.g.:
- Azithromycin:
- < 6 months: 10 mg/kg/day for 5 days.
- ≥ 6 months: 10 mg/kg (max 500mg) on day 1, then 5 mg/kg/day (max 250 mg) on days 2 – 5.
Management of contacts
Prophylaxis for all household contacts and for health care workers with close contact:
- Azithromycin: as for treatment above.
REFERRAL
- Children with seizures or encephalopathy for further evaluation.
- Patients requiring intensive care, where none is available on site.